[...]... accurate Student C's results are both precise and accurate 20 CHAPTER 1 Chemistry: The Central Science Using Units and Solving Problems Solving problems correctly in chemistry requires careful manipulation of both numbers and units Paying attention to the units will benefit you greatly as you proceed through this, or any other, chemistry course Conversion Factors A conversion factor is a fraction in... ) to match both 5.46 and 49.91 I (Continued) Note that it is the number of pennies (3), not the mass, that is an exact number 18 CHAPTER 1 Chemistry: The Central Science Solution (a) Think About It It may look as though the rule of addition has been violated in part (e) because the final answer (5.537 X 103 g) has three places past the decimal point, not two However, the rule was applied ? to get the... and that a foot is not equa l to thousands of meters! = How Can You Enhance Your Chances of Success in Chemistry Class? calculation Always carry at least one extra significant fig ure in intermediate calculations Make sure that the final answer has the correct number of significant figures Success in a chemistry class depends largely on problem-solving ability The sample problems throughout the text are... apprentice tailors (X, Y, and Z) are assigned the task of measuring the seam of a pair of trousers Each one makes three measurements The results in inches are X (31.5, 31.6, 31.4); Y (32.8,32.3, 32,7 ); Z (3 1.9, 32 .2, 32.1) The true length is 32.0 in Comment on the precision and the accuracy of each tailor's measurements Section 1.6: Using Units and Solving Problems Problems 1.54 Carry out the following... states in the United States is 55 mph What is the speed limit in kilometers per hour (1 mi = 1609 m)? The "normal" lead content in human blood is about 0.40 part per million (that is, 0.40 g of lead per million grams of blood) A value of 0.80 part per million (ppm) is considered to be dangerous How many grams of lead are contained in 6.0 X 10 3 g of blood (the amount in an average adult) if the lead... child Lady Montagu campaigned for the practice when she returned to England, and despite opposition from doctors and religious leaders, inoculation came into common use It remained the primary defense against the scourge of smallpox for decades-until Jenner developed the practice of vaccination 1 2 a) a doctor b) Turkish c) severely scarred by smallpox d) a member of a prominent British family 3 The author... b) compare Lady Montagu to the doctors and religious leaders in England c) explain why Lady Montagu herself did not undergo the engrafting procedure d) emphasize Lady Montagu's fascination with other cultures The main point of the passage is that a) Lady Montagu survived smallpox as a child b) Lady Montagu brought the practice of engrafting from Turkey to England c) Doctors in eighteenth-century England... your ballpark estimate from the Strategy step If your result does not have the appropriate units, or if its magnitude or sign is not reasonable, check your solution for possible errors A very important part of problem solving is being able to judge whether the answer is reasonable It is relatively easy to spot a wrong sign or incorrect units, but you should also develop a sense of magnitude and be able... probably need to review the corresponding sample problem and the concepts that led up to it Solution: Using the necessary equations, constants, and other information, calculate the answer to the problem Pay particular attention to the units associated with each number, tracking and canceling units carefully throughout the calculation In the event that multiple calculations are required, label any intermediate... which the original substance is converted to a different substance Physical and chemical properties may be intensive (independent of the amount of matter) or extensive (dependent on the amount of matter) Chemistry is the study of matter and the changes matter undergoes • Physical properties are those that can be determined without the matter in question undergoing a chemical change A physical change is